1. Field of the Invention
The present invention relates to a ball valve comprising a spherical shutoff body which is moveable between closure and open positions by rotating a control shaft rotatably mounted in the ball valve housing.
2. Description of the Prior Art
Ball valves have a small space requirement for a given flow cross-section and are therefore widely used in particular in mobile equipment. Thus, ball valves are widespread as shutoff members in fire-fighting equipment. The shift travel between open position and closure position in ball cocks or valves is generally only 90.degree. angle of rotation. The opening or closing of a ball valve is thus possible even under pressure within a fraction of a second. However, too rapid opening or closing leads to pressure peaks which can overload the conduit elements. Pressure peaks occurring on sudden opening or closing of ball valves can also lead to uncontrolled and dangerous movements of loosely laid conduits or hoses. Actuation of ball valves under pressure must therefore take place slowly enough to avoid occurrence of potentially damaging high pressure peaks. To presently meet this requirement operation by trained personnel is necessary. Nevertheless, in fire-brigade uses operating errors can be made which lead to damaging of the material or endangering of the personnel.